Prior art known to the present inventor includes:
U.S. Pat. No. 4,084,914, granted Apr. 18, 1978 to Humphrey et al, which discloses a self-erecting highway guide post, which comprises a pair of arcuate channel members which are secured together to form a hollow element and may include integrally constructed barbs or holes to resist removal of the channel once inserted.
U.S. Pat. No. 4,298,292, granted Nov. 3, 1981 to Sweeney, which discloses a flexible delineator member and anchor disposed in a rigid pilot plate such that when the anchor and pilot plate are driven into the ground or road surface, the bottom end of the delineator follows the bottom edge of the pilot plate.
U.S. Pat. No. 4,522,530, granted Jun. 11, 1985 to Arthur, which discloses a traffic delineator wherein the lower end portion of the tube includes outwardly projecting spring fingers which positively lock the device into the ground.
U.S. Pat. No. Re. 32,045, granted to Schmanski Dec. 10, 1985, discloses a fiber glass reinforced plastic post, including vertical rigid ribs to assist in driving the post into position.
U.S. Patent No. Des. 337,129, granted Jul. 6, 1993 to Sandy, which discloses a sign mounted upon what appears to be a synthetic post.
U.S. Pat. No. 5,620,277, granted Apr. 15, 1997 to Cole, Sr. et al, which discloses a marking device, including at the lower end a slot for receiving an anchoring device, including outwardly flared fingers.
U.S. Pat. No. 6,375,385 B1, granted Apr. 23, 2002 to Kennedy, which discloses a laminated flexible support, including a plurality of individual members, the flexibility being adjusted by tension members placed along the length of the laminated element.